Alloy and manufactures



Patented May 3, 1938 signer, by mesne assignments, to ltnstlesc Iron and Steel Corporation, Baltimore, Md., acorporation ofv Delaware Serial No. '28 75 No Drawing. Applicationalnne 25,1935. 2 1

10 Claims. (01. 15-12;

This invention relates to chromium-nickel alloy irons and steels and to-articles and manufactures of the same. v

Among the objects of my invention is the pro- 5 duction of alloy irons and steels, which are strong, tough and durable, which are readily workable, as by forging, upsetting, and hot and cold rolling, which readily lend themselves to a variety of shaping and forming operations, such as punching and blanking and various machining operations, such as cutting, drilling and threading, which are readily welded employing known methods and equipment, all as inthe production of a variety of articles, products or manufactures, such as seamless tubes and pipes, fluid valves, flanges and bolts, pans, vats and tanks, internal combustion engine valves and valve seats, exhaust stacks, turbine buckets and, nozzles and like articles, products and manufactures, especially suited for high temperature duty in the presence of corrosive or corrosion-fostering agents. I r

The invention accordingly consists in the combination of elements, composition of ingredients as and mixture of materials, and in thearticles,

products and manufactures of the same, as described herein, the scope of the application of whichis indicated in the following claims.

As conducive to a clearer understanding of certain features of my invention it may be noted at this point that theaustenitic chromium-nickel irons and. steels (irons and steels containing approximately, 10% to 25% chromium, 7% to 15% nickel, and the balance substantially iron) are used in the production of a wide variety of corrosion-resistant and mildly heat-resistant products or articles of manufacture. Thus, these austenitic irons and steels, especially the 18-'-8 irons and steels (irons and steels containing 18% chromium, 8% nickel, and the balance substantially iron) may be used in a number of interior or exterior architectural applications, such as decorative trim, ornamentation and fixtures. Likewise, these irons and steels may be employed for a variety of kitchen, soda fountain, dairy and hospital applications, as in cooking and serving utensils, containers and appliances, counter and furniture trim and the like, where permanently 50 bright corrosion-resistant metal capable of withstanding the corrosive action of various fruit and vegetable acids, is desired. Similarly, these irons and steels are widely adapted for various chemical plant apparatus and equipment where metal re- 1 5 sistant to the corrosive attack of acids, alkalies and saltsat room temperature, or slightly elevated temperatures, is required.

These austenitic chromium-nickel irons and steels, however, are not satisfactorily adaptable to extremely high temperatureduty, especially 5 high. temperature duty under strongly oxidizing" or corrosive conditions, largely because of the susceptibility of these irons and steels-to intergranular corrosion.

One of the outstanding obiectsof my invention 1 is the production of strong, tough and durable modified chromium-nickel alloy irons and steels, which are readily worked or formed intoa variety of articles, products and manufactures, which are highly resistant to scaling, pitting and inter- 15 granular corrosion and which are resistant to wear and abrasion, a1l.at high temperatures and under a variety of corrosive conditions over long periods of use with a minimum of break-down, replacement and repair. P i

As illustrative of the practice of my invention, modified chromium-nickel alloy iron or steel analyzing approximately, 18% chromium, 8% nickel, 1.5% to 2.5% cobalt, 2.5% to 3.5% molybdenum, 1.5% to 2.5% manganese, .07% to .1% as carbon andthe balance substantially iron, with the usual percentages of silicon, sulphur and phosphorus,- is produced in a suitable manner, as for example as described in Patent No. 1,925,182

granted September 5, 1933 to Alexander L. Feilcl g and entitled Process of the manufacture of. rust- I less iron. The metal is first produced as ingots which are fashioned into blooms or billetsin accordance withknown methodsand converted into tube rounds or conveniently rolled into sheet barand strip bar sizes. The tube rounds are then pierced, forming seamless tubes, and the bar sizes are annealed and pickled and, for example, cold rolled into sheet or strip of desired thickness.

My alloy iron or steel is essentially austenitic 40 in structure although it containscertain new constituents in the form of complex ferrites and carbides. The alloy iron is especially resistant to corrosion and scaling as well as to embrittlement and fatigue at high temperatures'inthe presence 'of a variety of corrosive agents, including sulphur-bearing gases and vapors, 'in'addi-' tion to the agents normally present in the atmosphere, and has a life under these conditions greatly in excess of that of known and/or used austenltic chromium-nickel irons and steels. While a forgedsampleof alloy iron analyzing approximately, 18% chromium, 8% nickel, 2% cobalt, 3% molybdenum, 2% manganese, .10%

carbon, and the balance substantially iron, has

a life of several hundred hours under the accelerated test conditions of a stress of 8,000 pounds per square inch, at a temperature of 1500 F. under the normal oxidizing atmospheric conditions, known chromium-nickel iron analyzing approximately, 18% 8% nickel,

.10% carbon, and the balance substantially iron, has a life under these conditions of less than ten hours.

My modified chromium-nickel alloy iron or steel furthermore lends itself to a variety of working and forming operations, either from sheet, strip or bar stock. The metal'readily lends perature duty, as in boilers, condensers, oil cracking stills, evaporator units and the like. (Where a welding operation is employed the articles, products or manufactures are preferably heat-treated in accordance-with well known methods after the welding operation is completed in order to assure maximum chemical resistance in use and achieve maximum life.) These various articles, products and manufactures are employed in the oil, photographic film, dairy, canning, paint, dye and like chemical andsemi-chemical industries, giving long life with a minimum of-inspection, replacement and repair. e

In addition, my modified chromium-nickel alloy iron or steel is worked or formed, as above indicated, achieving a further variety ofhigh temperature .duty articles, products or manufactures, such as internal combustion engine valves, valve seats, exhaust manifolds and stacks, especially those used inautomotive and aviation duty, where the scour ofxextremely hot gases bearing corrosive and corrosion-fostering agents is encountered. Likewise, the metal is employed in-gas turbine buckets, nozzles and similar parts requiring strength, toughness, rulstance .to impactand shock and resistance to corrosion and scaling at high temperatures in the presence of strongly corrosive agents.;

' durable, corrosion-resistant and heat-resistant and that they readily lend themselves to working or forming into a variety .of commercial products, a number of which are indicated above, which are especially adapted to withstand continuous high temperature duty over long periods of time and under the many varying conditions encountered in actual, practical use. i

While as illustrative of the practice of my invention, chromium-nickel alloy irons, and steels containing approximately, 18% chromium, 8% nickel, 1.5% to 2.5% cobalt,2.5% to-3.5% molybdenum, 1.5% to 2.5% manganese, .0'l% to .l%

carbon, and the balance substantially iron, are

specifically described, good results are achieved where the chromium content ranges between 10% and 25% and the nickel content between 7% and 15%. Similarly. good results are achieved where the cobalt content ranges between about scribed, alloy iron .5% and 3%, the molybdenum content mm 5% and 4%, the manganese between .57, and 4% and the carbon content between .03% and 2%. 1

The steels of the higher chromium, nickel, cobalt, molybdenum and manganese contents 1 are used especially in the. production of a variety of .cast articles andmanufactures, such as furnace parts, ore treating and handling apparatus; high temperature conveyor parts and equipment and-like machinery subjected to corrosive and abrasive 4 conditions, all under high temperature conditions of operation. a

As manypossible embodiments may be made of my invention and as many changes may be made in the embodiments hereinbefore set forth, it is to. beunderstood thatall matter'described herein is tobe interpreted not in a limiting sense.

I claim: 1. In a comnosition'of matter of the classdeor steel which pouesses .a good length of life under high temperature conditions, said alloy iron or steel comprising as essential ingredients, approximately,- cent chromium, 7 per cent to per cent to 3 per cent cobalt, .5 per cent to 4 per cent molybdenum, .5 per cent to 4 percent manganese. .03 per cent-to .2 per cent carbon, and

the balance substantially all cent cobalt, 2.5 per cent to 3.5 per cent molybdenum, 1.5 percent to 2.5 per cent manganese,

.03 per cent to .2 per cent carbon, and the balance substantially all iron; I

3. In a composition oi' matter of the class described, alloy iron or steel which possesses a good length of life under high temperature conditions,

said alloy iron or steel comprising as essential ingredients, approximately, 18 per cent chm-- mium, 8 per cent nickel, 2 per cent cobalt, 3 per cent molybdenum, 2 per cent manganese, ;.i0 per cent carbon, iron. i 4. In manufactures of the class wrought alloyiron articles which possess good life under high temperature conditions, said articles comprising as essential ingredients, approximately, 10 per cent -to 25 per cent chromium, -'l' per cent to. percent nickel, .5 per cent to"3 per cent cobalt, .5 per cent to 4 per cent molybde num, .5 per cent to 4 per cent manganese,'.03 per cent to .2 per cent carbon, and the balance substantially all iron. j

5. In manufactures of the class described cast alloy iron articles which possess good life under high temperature conditions, said articles comprising as essential ingredients, approximately,

as illustrative, and

lo'per'cent to '.per 15 per cent nickel, .5

and the balance substantially all 10 per cent to 25 per cent chromium, 7 per cent to 15 per cent nickel, .5 per cent to 3 per cent cobalt, .5 per cent to 4 per centmolybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon,'and the balance substantially all iron. Q.

6. In manufactures of the class described alloy iron sheet and strip which possess good life under high temperature conditions, said sheet and strip comprising as. essential ingredients, approximately, 10 per cent to 25 per cent chroinium,'7 per cent to 15 per centnickel, .5 per cent to 3 per cent cobalt, .5 per cent to 4 per cent molybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon, and the balance substantially all iron.

7. In manufactures of the class described, alloy iron or steel tubes of good life under high temperature conditions, said tubes comprising as essential ingredients, approximately, 10 per cent to 25 per cent chromium, 7 per cent to 15 per cent nickel, .5 per cent to 3 per cent cobalt, .5 per cent to 4 per cent molybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon, and the balance substantially all iron.

8. In manufactures of the class described, coldrolled alloy iron or steel sheet and strip comprising as essential ingredients, approximately, 10 per cent to 25 per cent chromium, 7 per cent to 15 per cent nickel, .5 per cent to 3 per cent cobalt,

.5 per cent to 4 per cent molybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon, and the balance substantially all iron.

9. In manufactures of the class described, coldrolled alloyiron or steel sheet and strip comprising as essential ingredients, approximately, 18 per cent chromium, 8 per cent nickel, 1.5 per cent to 2.5 per cent cobalt, 2.5 per cent to 3.5 per cent molybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon, and the balance substantially all iron.

10. In manfactures of the class described, coldrolled alloy iron or steel sheet and strip comprising as essential ingredients, approximately, 10 per cent to 25 percent chromium; 7 per cent to 15 per cent nickel, 1.5 per cent to 2.5 per cent cobalt, 2.5 per cent to 3.5 per cent molybdenum, .5 per cent to 4 per cent manganese, .03 per cent to .2 per cent carbon, and the balance substantially all iron.

- VSEVOLOD NICHOLAS KRIVOBOK. 

